The City of Allen was contacted by homeowners in the Wimberly (Twin Creeks Estates) neighborhood with concerns about fast-moving water through their backyards. A tributary of Rowlett Creek, which long-existed before the homes were built, runs through the backyards in a drainage easement. The tributary is shallow and wide, so when a rain event occurs, the spread of water is not necessarily deep, but it is intimidating because of the width of the flow of water (occupying nearly the entire backyard). Furthermore, the leaves and other matter that flows through their backyards toward Rowlett Creek is caught on the homeowner's fences, creating a difficult maintenance situation, beyond the reasonable effort for an average homeowner. The result is backyards that cannot ever achieve a stand of grass, remain muddy and wet continuously, and requires a solution that exceeds the abilities of a single homeowner to undertake alone.
All of this is the result of an intentional effort to save trees and leave the tributary in 'a natural state' at the time of subdivision development. In hindsight, the unintended consequences of preserving this tributary has become a private property burden on a few homeowners, inundated by flows from others upstream (as far away as Cypress Meadows). Compounding the issue is that, at the time the homes were built (2013), the region was experiencing record drought conditions, and these drainage conditions were not apparent to the homeowners until a few years after living in their homes.
The solution has not been easy to derive, since the drainage easement across the backyards is a private maintenance easement and the drainage infrastructure (drainage pipes and streets) within Wimberly (a gated community) is also privately-maintained by the HOA.
The residents desired a piped solution to route the overland stormwater flows in a buried pipe through their backyards. Convinced of this solution, the homeowners funded an engineering design to bid the project and ascertain cost to install a pipe to alleviate the drainage concerns. Publicly bidding the project revealed a construction cost of $225,000 (rounded). City staff negotiated with the homeowners that the cost of constructing the project should not be borne entirely by the City and the homeowners agreed to collectively fund half of the project ($112,500).
The Homeowners Association (HOA) will not contribute financially to the project and required certain commitments from all parties. Specifically, each homeowner committing (in writing) to backyard restoration/beautification within a specific timeframe. This pipe will be proposed to be maintained by the City in a new 30-ft easement as the HOA does not want to inherit maintenance responsibility.
The award for construction is being presented to Council as a separate item on the same agenda.